0566-reshape-the-matrix.js

/**
 * 566. Reshape the Matrix
 * https://leetcode.com/problems/reshape-the-matrix/
 * Difficulty: Easy
 *
 * In MATLAB, there is a handy function called reshape which can reshape an m x n
 * matrix into a new one with a different size r x c keeping its original data.
 *
 * You are given an m x n matrix mat and two integers r and c representing the
 * number of rows and the number of columns of the wanted reshaped matrix.
 *
 * The reshaped matrix should be filled with all the elements of the original
 * matrix in the same row-traversing order as they were.
 *
 * If the reshape operation with given parameters is possible and legal, output
 * the new reshaped matrix; Otherwise, output the original matrix.
 */

/**
 * @param {number[][]} mat
 * @param {number} r
 * @param {number} c
 * @return {number[][]}
 */
var matrixReshape = function(mat, r, c) {
  const flat = mat.flat();
  const result = [];

  if (flat.length !== r * c) {
    return mat;
  }

  while (flat.length) {
    result.push(flat.splice(0, c));
  }

  return result;
};